JULIAN Assange does not have secret sealed charges filed against him, a top US law official insists.

In an interview with the Washington Post, the anonymous source said the ongoing rumours that a three-year-old grand jury investigation into the WikiLeaks founder had led to secret charges against him were false.

"Nothing has occurred so far," the official said. "If Assange came to the US today, he would not be arrested. But I can't predict what's going to happen. He might be in six months."

Julian Assange has been holed up in an Ecuadorean embassy in London for more than a year after his WikiLeaks website caused the US and its European allies severe embarrassment by leaking secret diplomatic and military documents.

Assange faces allegations of sexual assault in Sweden and lost a series of court appeals in Britain to avoid extradition. There is a warrant in Sweden for his arrest.

The fugitive insists the Swedish charges are false and designed only to have him detained in order for the secret US arrest warrant to be enacted.

Assange was granted asylum by Ecuador in June 2012 and has been trapped inside its London embassy, under constant police surveillance, ever since.

"We will treat this news with scepticism short of an open, official, formal confirmation that the US government is not going to prosecute WikiLeaks," WikiLeaks spokesperson Kristinn Hrafnsson told the Washington Post. "It is quite obvious that you can shake up an indictment in a very short period of time."

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